Curious; why is it that Loki keeps calling/referring Thor as his "brother" despite the fact that we've seen him emphasize on how he and Thor "aren't" brothers?

To bring guilt in him. Like he didn't visit Loki, his brother, in prison for almost a year (Thor probably just cant bring himself to look at him after the events of Avengers). And because they are and always will be brothers, but I doubt this were Loki thoughts at the moment=).